Impulse transmitter



@655. 15, 1935. H. W GOFF 2,017,438

IMPULSE TRANSMITTER Filed March 29, 1954 lNVENTOR w GOFF A TTORNEV Patented Oct. 15, 1935 Harold W. Gofl,

IMPULSE TRANSMITTER Great Neck, N. Y., assignor to ell Telephone Laboratories, Incorporated, New York, N. Y., a corporation or New York Application March 29, 1934, Serial No. 717,963

2 Claims.

This invention relates to impulse transmitters and particularly to calling dials of the type commonly employed matic telephone systems.

in automatic and semi-auto- Telephone dials or impulse transmitters to which this invention is applicable for use as shown in Patent 1,860,535 to May 31, 1932, for example, ge

H. W. Goff, dated nerally consist of a cup-shaped mounting, a number plate supported by the cup-shaped mounting, a clamping ring for securing the number plate, a centrally disposed shait journaled in a mounting, a fingerwheel secu bushing carried by the red to the top disposed end of the shaft and a gearing mechanism actuated through the operation of the fingerwheel ior actuating the pulsing contacts.

In such call transmitters it was found that dust became deposited on the operating parts of the impulse mechanism and that this dust reached these parts through the clamping ring and the fingerwheel.

According tois provided the number plate on the space between underside of the this invention a call transmitter with an improved ring for clamping the mounting while cooperating with an improved fingerwheel for preventing the entry of into the casing to render the interior of this tially dust proof and dust or other foreign particles thus formed to such a degree as mounting substanthereby insuring the proper operation of its impulse actuating mechanism for a maximum length of the interior of the cup-shap time, means secured to ed mounting being provided for engaging portions of the clamping ring for holding it in adjuste d relation with the fingerwheel and the number plate in adjusted position on the cup-shaped mounting.

These and other be readily understood features of the invention will from the following detailed description made with reference to the accompanying drawing in which:

Fig. 1 is a plan view of a telephone dial with the fingerwheel and numb broken away showing ing ring and its associated assembled relation.

er plate partially the number plate clampsecuring spring in Fig. 2 is a side view oi the dial shown in Fig. 1

showing a number of operating parts in section taken along the line 2-2 and looking in the direction of the arrows; and

Fig. 3 is a perspective view of the removable clamping ring partially broken away to disclose the integral lugs with which its securing spring engages when the ring is set in adjusted position.

It is believed unnecessary to describe in detail the call transmitter mechanism or its operation-as this part 01 the call transmitter is fully disclosed and described in U. S. Patent 1,860,535 above mentioned, and forms no part of the present invention. 5

The dial casing or mounting in is provided with a circular recess H which iorms a shoulder portion upon which the outer edge of the number plate 12 rests, as is clearly shown in Fig. 2.

The fingerwheel l3, which is mounted on the 10 centrally disposed shaft 25, is provided with a circular groove M which is oi sufficient depth and width to accommodate the upper edge 01' the clamping ring 15 in such a manner as to permit the fingerwheel Hi to ireely rotate. 15

The clamping ring or shield l5 thus formed is provided with a circular shoulder IS, the upper edge of which rests on the inner edge or the annular number plate l2 when the ring is set in position. 'Iwo integral lugs I! are located on the 20 inner lower edge of the collar l5 and are oppositely disposed.

The dial casing I0 is provided with a boss l8 which is tapped to receive the screw i9. A hairpin-shaped spring 20 is secured in position on the 25 casing boss l8 by means of the screw i9 as shown in Figs. 1 and 2. The extreme end portions of the clamping spring 20 are adapted to engage the ring lugs I1.

The horizontal plane in which the lugs ll of 30 ring l5 are located when the collar is set in position, is higher than that of the normal position of spring 20, and the end portions of spring 20 are separated by a distance greater than the internal diameter of the collar l5 so that, aiter the spring is made last to the dial casing, the finger-like extensions are forced nearer together and lifted from their normal position to efiect engagement with the lugs l1. It is readily understood therefore that when the end portions of the spring 20 are brought into operative association with the lugs [1, they exert a downward pressure and an outward pressure on the lugs i1 and inner surfaces of the ring l5 respectively. In this manner the ring I5 is firmly held in position against the inner edge oi the number plate l2 and holds the number plate l2 in adjusted position in the shoulder portion or recess ll formed at the top disposed edge of cup-shaped mounting Ill.

The integral lugs H are provided with an external flange which prevents the spring ends from being accidentally dislodged.

The provision of the clamping ring I! with its upper edge extending in the circular recess ll 55 in the underside of the fingerwheel l3 decreases the area of the air path between the fingerwheel and the edge of the clamping ring to a degree as to make the interior of the mounting substantially dust proof While the spring 20 afiords a simple and convenient arrangement for collectively holding the clamping ring on the number plate and the number plate on the mounting.

What is claimed is:

1. A call transmitter mechanism comprising an annular number plate, a mounting for said mechanism provided with a flange for mounting said number plate, a shaft journaled in said mounting, a fingerwheel carried by said shaft in superposed spaced relation to said number plate and provided with an annular groove, a ring resting on the inner edge of said number plate and extending therefrom into the groove in said fingerwheel, said ring constituting a barrier between said number plate and said fingerwheel, and means for securing said ring on the inner edge of said number plate.

2. A call transmitter comprising a mounting, a number plate, a shaft journaled in said mounting, a fingerwheel carried by said shaft in spaced relation to said number plate, a ring-shaped member engaging said number plate and having One of its edges extending in a circular groove in said fingerwheel, and spring means secured to said mounting and engaging diametrically disposed portions formed with said ring for securing said number plate on said mounting.

HAROLD W. GOFF. 

